Process for the extraction of sulfur from metallic sulfids.



STATES PATENT OFFICE.

WILLIAM AUGUSTUS HALL, OF NEW YORK, N. Y. I

. rnocnss Fort THQE nx'rmo'rron or SULFUR mom iii-Ethnic suns-roe.

No Drawing.

Specification of letters Patent.

Patented nee. cameras Application filed October 10, 1912. Serial No. 725 ,oe4.

Processes for the Extraction of Sulfur from Metallic Sulfids, of which the following is a specification.

This invention relates to an improvement in the process described in the specification of my co-pending application for patent Serial Number 725,026, filed concurrently herewith. In the specification accompanying that application I described a process of producing sulfureted hydrogen from metallic sulflds e. 9. iron pyrites by submitting the pyrites to the combined action of a re dticing flame (which decom oses it without. producing any apprecia 1e oxidation) and steam intended to furnish-nascent hy-.

drogen and nascent oxygen for the purposes described in said application, the operations being carried out under such conditions that fresh surfaces of' the p rites are continuously exposed to the action of the reducmg flame and of the steam.

The object of my present invention is to.

extract the sulfur from p rites or other sulfid ores, principally in t e form of elemental sulfur, and not principally in the form of H S, as in the process of my other application above referred to.

In the practice of the prior process referred to, I employed in conjunction with the direct reducing flame a considerable amount of steamin order that the nascent hydrogen thereof :would combine with the sulfur vapor to form H S and that the nascent oxygen of the steam would supply a stableequivalent to the iron of the pyrites. v

In accordance with the present process I Suppl to the furnace in conjunctlon with pau'vre or producer gas than would be at or about 700C and p' fer blgbgtwg i after refer-re practicable were no steam had, thus The temperature-in the present process is, by means of limiting the aniount'of maintained at or above thetempei'atfire'at which sulfur distil's from the ore, 91}! 700 and 900 C, At-tliese 'ttmp ratui esgand bytlie action'of a reducing flame', the pl-iii; cipal part of the sulfur of the pyrit es dr' other sulfid ore, is drivenoif in. the. form of elemental sulfur,-directly byjdi'stillat ieii',

and the remainder of the sulfur is drlven off from the pyrites, by reaction with the steam to produce H 81 If this proper amount of air were admitted without any steam, then the discharge would contain-a considerable amount of S 2 wliichini lit be lost; but by admitting the steam; tlie formed is taken care of the H S also formed, in accordance with the well known sulfur precipitatedtherebyis carried over with the sulfur vapor and depositedtherer with. Inthis way the steam takes careo'f any excess air that may pass into the fur- .nace and intended for the perfect'co'mbiis;

effected) heated internally by dii'ect v anie produced from a mixture of g'az m tre or producer gas and-air, the mountain; admitted bein so regulatedthatthe fl, l'e produced while not necessarily a highly'r'educing flame, is of S acter to combine with any free oxygen. Steam 'or water which would be trans formed into steam, is passed in thi ough' inlets suitably disposed, preferably ihla'tgei quantity toward the lower end of the furcint' reducing char 7 nace, the furnace being provided with agas outlet from which extends a 'l charge pipe. Into this discharge pipe steain' may also be (passed with the object hereiii been raised'to the proper dftemperto. when the furnacehsisin the furnace. If this were not done much less sulfur would be discharged. The products of combustion pass up through the long pipe in which the temperature is reduced several hundred degrees and the products into H S and S0,.

of combustion pass out surcharged with yellow sulfur vapor without any appreciable admixture of $0,. This fact has been determined by analysis of the gases. Thedischarge pipe leads the sulfur vapor and products of combustion to a gas-washing apparatus such as the well known Thiesen apparatus where the atmosphere is quickly clarified bythe precipitation of the finely divided sulfur in the water of the washer and from this it is extracted by any desired means.

The reactions that take place in the interior of the furnace are :-(1) A-decomposition of the pyrites FeS and distillation of sulfur in the form of sulfur vapor a small portion of which may combine with any excess oxygen present. Very much over onehalf of the total sulfur in the pyrites can be distilled off without first being converted (2) A decomposition of the steam by the lower sulfids of iron, while steam which may be passed 1 at a high temperature forming H S, Fe,O and some Fe O,,. (3) The combination of this H 8 with any SO present, forming elemental sulfur b the well.known reaction 2H S+SO =2 O+3S which sulfur is carriediover to the condenser along with the distilled sulfur and roducts of combustion and (4) the formation of COS from some of the excess of CO contained in the gas pawvre or producer gas. This would ordinarily cause a considerable loss in sulfur. I meet this dificulty by admitting1 more 'nto t e discharge pipe as already described, where at lower temperatures it combines with the COS forming H S and CO this H S also combines with excess of SO in the same manner as does the H 8 generated in the furnace as hereinbefore described.

'Without steam there is a tendency for the iron sulfids to fuse slightly and for the par ticles of pyrites to adhere to ether but this is largely overcome by the a 'ssion of the smallamount of steam and by. the continuous agitation. The decomposition of the H 0 of the steam by the hot iron forms F6 0. and thus tends to break down and disintegrate the coarser pieces of the pyrites.

While I have described my process in detail as applied to the treatment of pyrites it is to be noted that this process is as stated above, usefulin connection with sulfid ores generally, and is not restricted to the treatment of pyrites. Among the other materials which I have treated according to this process, are pyrrhotite and'artificialferrous sulfid (FeS). Even when using these materials, whichfcontain much less sulfur than does pyrites, I can remove the major portion of the sulfur therefrom by direct distillation.

It will be seen that*in my process, a largev part of the sulfur is driven off from the pyrites in the form of free or elemental sul fur, and not as compounds thereof, S0 and H S, as in some of the processes heretofore proposed. The cause of this is the fact that a reducing flame, in contact with the 'ore, is

employed, together with the fact that asmall amount of steam is admitted.

'The; removal of both fixed and feeble atoms of sulfur, from sulfid ores broadly, and specifically from those varieties of sulfid ore which do not contain any material amount of pyrites or other ore containing both fixed and feeble atoms of sulfur, is not claimed herein, but forms the subject matter. of my copending application Serial No. 770,946, filed May 31, 1913.

Having described my invention what I i claim and desire to secure by LettersPatcnt of the United States is 1. In the production of sulfur .from ores containing considerable amounts of pyrites, subjecting said ore to the action of a reducing flame and of a limited amount of steam which amount is in itself insufficient to produce considerable amounts of H 8, -but sufficient to prevent substantial lossiof sulfur due to formation of materialquantities'of SO 'andCOS.

2. A'process of extracting sulfur from amounts of pyrites, which comprises agitating the sulfid and simultaneously subjecting the same to the combined action of a direct reducing flame and of a small amount of H 0.

3. A process of extracting sulfur from subjecting such sulfids to the simultaneous metallic sulfids, -containing considerable action ofa reducing flame and of "a "relatively small volume of steam while causinegj fresh surfaces of the sulfids to be-expos throughout the' operation. we V A 4. A process of extracting sulfur from metallic sulfids; which comprises subjecting the sulfids to the action of steam and of a reducing flame produced by combustion of producer gas, reacting with steam on any carbon oxy-sulfid that may be formed to produce sulfureted hydrogen and carbon dioxid and reacting on the sulfureted hydrogen with sulfur, dioxid to precipitate sulfur.

5. A processof extracting sulfur from metallic sulfids which comprises agitating the sulfids and simultaneously subjecting the same to the combined action of a direct reducing flame and of a small amount of steam, while maintaining the gases evolved ata pressure exceeding normal atmospheric pressure. V

6. In the production of free sulfur from sulfid ores, containing considerable quantities of pyrites, the step of subjecting a layer of said ore, to-the action of a reduclng flame, and of steam, while agitating. said ore.

7 In the production of freesulfur from pyrites ore, the step of subject-ing'a layer of sai d ore, to the action of a reducing flame, together with a small amount of steam,

8. Inthe production of free sulfur from ores containing pyrites, the step of subjecting a layer of said ore, to the action of a reducing flame, at a temperature at which freesulfur distils from said ore.

9. In the production of free sulfur from sulfid ores containing pyrites, the step of subjecting a la. er of said ore, to the action I of a reducing ame, together with suflici'ent steam to prevent the formation of material amounts of S0 and to decompose any COS formed. a

In" testimony whereof Ihave signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM AUGUSTUS HALL.

Witnesses:

HAROLD G. C. FAmwEA'rHnR, ALFRED T. BURBERY. 

